heeelp please.


4 replies to this topic
  • tino79

Posted April 06, 2009 - 08:41 PM

#1

i have a 08 wr450f, took it to the dealer to install the gyrt ais kit and the merge adjustable jet and the adjustuble fuel screw, When i took it home i tried it and worked realy good until i decided to take the exhaust restrictor off from the muffler:banghead: my bike has the hikups (like if i was running out of gas) at mid throttle. what can i do? should i mess with the adjustable jet kit or the fuel screw? forgive my stupidness this is my first bike soo everything is new to me thats why i bought the adjustable merge jet kit. HEEEEELLLP.

  • trailhead2004

Posted April 07, 2009 - 10:45 AM

#2

Hey Tino,

I'm going to try to be some help without actually being any help whatsoever.

Jetting is dependent on a lot of things, one of which is altitude, another being the restrictiveness of the exhaust system

What you did was change the exhaust enough that your jetting is no longer correct. My best guess from what you wrote is that you had the dealer put an adjustable leak jet in. That is typically to smooth out the transition when activating the accelerator pump (twisting the throttle more open).

My best guess is that you need to move up one size on the main jet. It won't be easy to get to but it's not impossible. I hope the dealer gave you a list of the jets/settings when he installed the adjustable leak jet. That will tell you what size main you have, then you buy the next one or two bigger jets and replace it one step at a time.

Alternatively, there is a long list/post of jet sizes that various people have used. If they put in all of the correct info, you should be able to find one that rides at an altitude near yours, and similar mods to the bike as for you. Look at their jet sizes and start from there.

HTH

trailhead :thumbsup:

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  • tino79

Posted April 07, 2009 - 05:13 PM

#3

sooo in another words this cant be fixed with just the adjustable jet kit? i thought that with the adjustable jet kit installed i didnt have to worry about taking the carb off to rejetted (didnt know about the main jet).know i know why the dealer didnt take the exhaust restrictor off, boy am i mad know. will call them tomorrow beacause with the ais removal installed it says to take the exhaust restrictor off but they didnt bother doing it so they wouldnt worry about rejetting it.

  • Krannie McKranface

Posted April 07, 2009 - 07:13 PM

#4

i have a 08 wr450f, took it to the dealer to install the gyrt ais kit and the merge adjustable jet and the adjustuble fuel screw, When i took it home i tried it and worked realy good until i decided to take the exhaust restrictor off from the muffler:banghead: my bike has the hikups (like if i was running out of gas) at mid throttle. what can i do? should i mess with the adjustable jet kit or the fuel screw? forgive my stupidness this is my first bike soo everything is new to me thats why i bought the adjustable merge jet kit. HEEEEELLLP.


I wouldn't go back to that dealer if they did only what you said.
1. Derestriction requires re-jetting
2. Stock jetting is way to lean to begin with
3. Adjustable leak jet is barely even needed until you derestirct.

You need to learn how to work on your own bike. It's not hard.

  • trailhead2004

Posted April 08, 2009 - 05:55 AM

#5

You need to learn how to work on your own bike. It's not hard.


Ahhh, be easy on the guy Krannie, he's a newb. He even said so.

Basically it sounds like Krannie and I are right though. I checked out the Merge website and they have an adjustable leak jet kit, accelerator pump spring, yadda, yadda, yadda. But no "adjustable jet kit".

They do have a tech support page with instructions for installation, tuning, carb specs, etc. http://www.mergeracing.com/tech/ It looks like it's a good place to start. But what you said about getting the main jet set up and maybe a pilot too is correct. Playing with the leak jet only helps bog on acceleration so you need to deal with that last.

Here's a couple of threads that might be a good place to start too.
http://www.thumperta...ht=carb jetting
http://www.thumperta...ht=carb jetting
http://www.thumperta...ht=carb jetting

And try a search on your own too. Think of good keywords and go to the advanced search and try to stick to either the WR or YZ forums (you can select individual forums or brands or whatever) and the technical forums. The info is out there you just need to dig it up.

BTW, the last thread I linked to is JD Jetting vs Yamaha GYTR AIS removal kit. Which it sounds like you had installed. I run the JD kit and parts of the Yamaha kit. Point is, that should give you good direct information.

Good luck, and try reading this one first.
http://www.thumperta...ad.php?t=444630

trailhead :thumbsup:




 
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